A fan arrangement of this type is known from DE 34 20 277 C3. There, the housing of the fluid friction clutch, said housing being equipped with the fan blades, was assigned either a mechanically actuated brake or a mechanically actuated retaining rod, in order to stop the fan wheel completely, for example during a cold start, and thereby prevent the cooling air generated by the co-rotating fan from delaying the heating of the cooling fluid of the internal combustion engine. Both the brake provided there and the positively acting retaining device are actuated via a memory element which changes its shape abruptly at a specific coolant temperature and, since the memory element provided there is a coil, frees the fan wheel to rotate from a specific coolant temperature, while below this coolant temperature, that is to say, for example, during a cold start, it retains the fan wheel. In devices of this type, the drive arrangement, in particular the fluid friction clutch, must be provided correspondingly with a brake or, as proposed there, with a hollow drive shaft, through which an axially displaceable retaining rod is guided. This is complicated and also does not permit subsequent refitting. The changeover operation can also be triggered solely by the coolant temperature, specifically irrespective of the air temperature which controls the supply or discharge of oil to or from the clutch and which is recorded via a bimetal.